Study on changes in cognitive function of elderly individuals certified for long-term care insurance

Objectives　To elucidate the changes in cognitive function in elderly individuals as observed in the results of a long-term care certification survey.Methods　The data were obtained from the long-term care insurance of 121 subjects who applied for benefit renewal between 2010 and 2011, in a city in Japan. The subjects were grouped into one of three groups (improved, maintained, or worsened) according to the change in status of overall cognitive function. Analyses were completed with this grouping as the main dependent variable and with sex, age, degree of independence at the initial insurance application in 2006, and levels of seven categories of cognitive function as independent variables.Results　There was a statistically significant association between age and deterioration of various cognitive functions. Sex had no significant effect on the rate of deterioration. The initial degree of independence was positively associated with the cognitive function change. Multivariate analysis (logistic regression analysis) incorporating age, sex, and initial degree of dependence as independent variables revealed that sex does not significantly influence the prognosis of cognitive function. Changes in the score of each of the seven cognitive functions were analyzed with ANOVA, with categories of functions and individuals as sources of variance. Both function category and individuals were significantly associated with deterioration. Among the seven categories of functions, "understanding daily activities" had the greatest deterioration, while "calling him/herself by his/her own name" had the least.Conclusion　Cognitive function, as observed in the long-term care certification survey, is more likely to deteriorate in elderly individuals and in those who were at higher levels of dependency index at the time of initial certification, and this effect is observed equally in men and women. Our results suggest that, in providing long-term care for elderly people, it may be useful to call the clients by their names and ask them to name themselves, as well as to try to improve their understanding regarding the daily activities by articulating the components of each activity.